Polymers crosslinked with reversible dynamic bonds such as hydrogen bonds show dynamic mechanical functionalities such as self-recovering ability. Here, we aimed to elucidate the effects of the structural flexibility of multiplexed hydrogen bonds (H-bonds) upon the mechanical properties of reversibly crosslinked polymers. We synthesized polybutadiene modified with vicinal diol (VDO), which was flexible and had multiple stable H-bonding modes, and urazole, which was rigid and showed only one binding mode. The mechanical properties of these two polymers were compared.According to the results of the rheological measurements, tensile tests, and cyclic tensile tests, the H-bonds between flexible VDO groups dissociated and reassociated more easily compared to those between rigid urazole groups, contributing to superior dynamic properties such as extensibility and self-recovery ability.

Fourier transform infrared spectrometer (FT-IR) is widely used for the chemical analysis of foreign substances that are mixed in or adhered to products. FT-IR is popular because it can provide chemical information on organic compounds and some inorganic compounds in a short time. However, the analysis of infrared spectra is often difficult for beginners. This review explains the methods of infrared spectral analysis for foreign substance analysis for beginners. First, the principle of infrared spectroscopy, the overview of qualitative analysis, and the methods of database search and spectrum reading are summarized. Especially, the skill of reading spectra is essential not only for estimating foreign substances, but also for showing the basis of the estimation and for analyzing mixtures. Next, the infrared spectra of 14 types of polymers that are most frequently detected in foreign substance analysis are shown, and the assignment of the main peaks and the classification methods of the polymers are explained.

Semiconductor was invented in Bell Labs in 1947. Since then, semiconductors have been developed as a result of the demands for diversification in the application, high speed, and high throughput. The evolution of semiconductor led to the miniaturization of transistors and the integration of electric circuit patterns. From the 1980s, in addition to the miniaturization based on the ultra-thin lithography line of semiconductors technology, lowcost mass production of the semiconductors was initiated based on the required characteristics. From what has been mentioned, there has been a demand to improve defectives.; for instance, the need for clean equipment, silicon Wafer cleaning, and highpurity materials.In this paper, we will outline the semiconductor front-end process, and will discuss the effects of the materials used in silicone cleaning and polishing, edging, lithography processes.

In recent years, with the expansion of the high-speed communication technology market, Low Dk and Low Df properties have become important for resins used in electronic devices. This influence is particularly noticeable in the material of printed circuit board applications, and various Low Dk and Low Df materials have been proposed to replace the commonly used epoxy resins. Especially, maleimide resins are gathered attention, because they can achieve not only high heat resistance and Low Df, but also have various reactivity. This report shows the relationship between the structure and properties of maleimide resins, as well as the formulations and properties of various curing systems.

Toward realization of “low-Carbon Society”, power semiconductors are becoming extremely important to use energy effectively. In recent years, application of SiC (Silicone Carbide) and GaN (Gallium Nitride) have been actively studied as a next generation semiconductor element that can achieve higher efficiency than Si (Silicone). Along with the application of SiC or GaN, characteristics such as high heat resistance are required for power devices. We developed epoxy resin molding compound (EMC) for power semiconductors and found some factors. Firstly, low ion impurity and high Tg of EMC improve the reliability such as HTRB. Secondly, EMC CTE matching with PKG components (Cu, SiC etc) is key point for temperature cycle. Thirdly, we found the new type resin structure based on the rigid biphenylene skeleton which can achieve both high Tg and high heat resistance. Furthermore, EMC is expected to contribute to worldwide environmental preservation measures and future development.